MacGregorSailors.com

I just found this on Al Gore's wonderful internet. Looks like what a lot of us have been needing to complete our galley. A portable microwave that runs on ac or dc power. Find it at www.thewavebox.com.

It might be a microwave but the literature appears to say
with a 12 volt power supply it has an output of 240 watts.
Empirically, compared to my home microwave, it will take
over eight minutes to boil one cup of water.

Lots of members of this board have expert elec knowledge.
Maybe they can do some math and properly rate this equipment.
L.

Indulgence wrote:It might be a microwave but the literature appears to say
with a 12 volt power supply it has an output of 240 watts.
Empirically, compared to my home microwave, it will take
over eight minutes to boil one cup of water.

Lots of members of this board have expert elec knowledge.
Maybe they can do some math and properly rate this equipment.
L.

I thought that wattage was only using the cig lighter. Direct 12V using the clips is full wattage I believe

More about it Here.

~Rich

Uhh... not so fast....

When the words ‘portable’ and ‘microwave’ first tickled our ears, we immediately thought ‘Coolest. Device. Ever.’ Oh, how we were wrong. With sturdy construction and a beefy handle, the WaveBox is definitely designed for portability. It’s also horribly underpowered, plagued by uneven heat distribution and lacks a window, all of which make cooking a frustrating endeavor. After a full 10 minutes, we pulled a half-popped bag of microwave popcorn from the WaveBox and noticed scorch marks on the bag from the included cooking rack. Microwave pizza took three times longer than the preset suggested, required two rotations, and still emerged as an unholy mass of burned and unmelted cheese. In theory, the WaveBox could be a useful tool for low-power purposes – like reheating coffee – but for the casual cook, it’s more trouble than it’s worth. —Roger Thomasson

WIRED Sturdy construction. Strong, grippy handle. Easy to port. Cleans up quickly. Multiple power options include AC, car adapter, and even direct-to- auto battery alligator clips.

TIRED Expensive. Uneven heat dispersal means periodic rotations are required. Suggested cooking times for traditional microwave ovens don’t apply. Lack of a window makes for an uncomfortable guessing game: Expect to mangle more than a few dishes. Presets don’t correspond to actual cooking time: the Popcorn preset claims 6 minutes., but we stopped after 15 and it still wasn’t fully popped.

kmclemore wrote:Uhh... not so fast....

When the words ‘portable’ and ‘microwave’ first tickled our ears, we immediately thought ‘Coolest. Device. Ever.’ Oh, how we were wrong. With sturdy construction and a beefy handle, the WaveBox is definitely designed for portability. It’s also horribly underpowered, plagued by uneven heat distribution and lacks a window, all of which make cooking a frustrating endeavor. After a full 10 minutes, we pulled a half-popped bag of microwave popcorn from the WaveBox and noticed scorch marks on the bag from the included cooking rack. Microwave pizza took three times longer than the preset suggested, required two rotations, and still emerged as an unholy mass of burned and unmelted cheese. In theory, the WaveBox could be a useful tool for low-power purposes – like reheating coffee – but for the casual cook, it’s more trouble than it’s worth. —Roger Thomasson

WIRED Sturdy construction. Strong, grippy handle. Easy to port. Cleans up quickly. Multiple power options include AC, car adapter, and even direct-to- auto battery alligator clips.

TIRED Expensive. Uneven heat dispersal means periodic rotations are required. Suggested cooking times for traditional microwave ovens don’t apply. Lack of a window makes for an uncomfortable guessing game: Expect to mangle more than a few dishes. Presets don’t correspond to actual cooking time: the Popcorn preset claims 6 minutes., but we stopped after 15 and it still wasn’t fully popped.

THey don't mention if their tests were with the cig lighter cable(lower wattage) or direct to the battery (full wattage).

Still haven't found an urge to put a micro in the M just the same

Paul

All in the vein of how much stuff can (should) you jam on a boat.

I loved bolting stuff to my Mac and was a gadget/ Mod freak like most of yous. See my "where did I put that waterline" post from years ago. Now that I have a smaller Boat and am limited on space, I will dispense with the frivolities and go for the necessities.

I want one of these!!

I think a fixed Microwave 650 watts ($65) built in with a 1000 watt inverter ($300) would be nice. Lets see how it works. Takes 15 watts to equal 1 amp of DC power source. 650 Watts devided by 15 watts =43.4 amps needed for 60 Min. devided by 5 min. of run time equals 8.68 amps. Since running the inverter power source, lets say it will take 10 amps 5 min. to run a Microwave 650 watts.
Thats not bad if you have 2-125 amp hr batteries for house.
Correct me if I am wrong.
So one could bring frozzen dinners, let thaw out to cook less time and have all the other benifits of Micro. Love 1-1/2 min. cup heat for coffee.
Dave

Tony D-26X_SusieQ wrote:I just found this on Al Gore's wonderful internet. Looks like what a lot of us have been needing to complete our galley. A portable microwave that runs on ac or dc power. Find it at http://www.thewavebox.com.

Microwave oven wattages are for output, or cooking power. The typical oven is only 65% efficient, so you need to add about 1/3 more to get your needed input power. Also, when choosing an inverter, be sure that the rating is for continuous use and not surge. Same with generators.

~Rich

Rich, If a Cup of water boils in AC current frow home @650 watts it will do almost the same on board with currect wireing and Inverter capable to do so with the twin 125 amp hr batteries. A Inverter that produces 12volt to 120 AC causes a 10-15% loss why I calculated the change. I agree Micro loss but not to 1/3 as my experance is less than 15% loss.
Bottom line is one could hook up to a 1000 watt Inverter (Surge is usually 200 more watts) and still run a 650 watt AC microwave oven on board.
The time I stated for boiling a cup of water on board would be about 1-1/2 min.
I use 75 and 160 watt inverters that plug in a cigeret lighter for all my AC appliances includeing 9 Inch DVD TV .
I had a Larger sailboat that had a 1500 watt inverter that powered a 900 watt Microwave and worked fine.
Your point in selecting a inverter with continuous output is important and also the surge power for startups.
Dave

Hamin' X wrote:Microwave oven wattages are for output, or cooking power. The typical oven is only 65% efficient, so you need to add about 1/3 more to get your needed input power. Also, when choosing an inverter, be sure that the rating is for continuous use and not surge. Same with generators.

~Rich

OK, folks. I have the answer to your electrical power problems. Who needs solar??

It will also reduce your waistlines!

Its not for me, mind you, but, anyone who really needs a few more amps to power a cell phone, or (if you're equal to Lance Armstrong), a microwave, should consider this item:

http://www.econvergence.net/electro.htm

A 1000w inverter will probably power a 650w microwave, but I know for a fact that it will power a 550w .5 cu. ft. Tappan "Space Saver" microwave. See http://macgregorsailors.com/modt/index.php?view=975

The "cooking power" wattage of microwave ovens is based on a duty cycle. Even on the high setting, the magnetron is not powered 100% of the time. It cycles on an off. The lower the power setting the less "on" time. Look at the data plate on the back of the oven. The "1000 watt" cooking power microwave in our Airstream is rated at 1500 watts. That includes the turntable motor, the cooling fan, and light bulb. On high, it cycles between about 1500 watts and about 100 watts. You have to consider this when calculating amp-hours drawn over time.

What you have to consider even more is that high current draws WAY more amp-hours out of the battery(s) due to the Peukert Effect. In other words, 6 minutes of 100 amp draw takes much more than 10 amp-hours out of the battery(s) relative to their amp-hour rating at 20 hours.

Peukert Effect - I always knew that batteries were rated on a constant discharge within a temp range. And was pretty sure that by reducing or increasing the discharge rate, the time constant was not linear but now we have it and in pretty definative terms. A quote from "ol Wiki" The Peukert law becomes a key issue in a battery electric vehicle where batteries rated at 20 hour (or even 100 hour) discharges are used at much greater rates of about 1 hour. I guess I will have to rethink my solar powered twin electric drives. I thought the South African's were building solar powered ocean going cats with electric drives.

Quick Google on "microwave input power" brought This page.

550 watts cooking power at 850 watts consumption. 550/850*100=64.7%. Close enough to 65% for me. 550+50%=825, so I misstated my original figures. You need to add 50%+ to the stated oven power to get to the actual 850 Watts needed to power it and the output power is 1/3 less than the input. AC, or DC makes no difference watts are watts. P=IE. A 650 watt oven will require 975 watts of input power and I would suggest that the load margin on a 1000W inverter is not enough for dependable usage. I would recommend at least a 1500W inverter for this purpose.

YMMV

~Rich